Download PDF
Synfacts 2006(9): 0956-0956  
DOI: 10.1055/s-2006-949232
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Organocatalytic anti-Mannich Reaction of Ketones

Contributor(s): Benjamin List, Michael Stadler
H. Zhang, M. Mifsud, F. Tanaka*, C. F. Barbas, III*
The Skaggs Institute for Chemical Biology and The Scripps Research Institute, La Jolla, USA
Further Information

Publication History

Publication Date:
23 August 2006 (online)

    Permissions and Reprints

Significance

An organocatalytic Mannich-type reaction using ketones as donor compounds and N-PMP-protected imines (PMP = p-methoxyphenyl) as acceptors is described. The catalyst employed is 3-pyrrolidinecarboxylic acid (β-proline). The reaction yields extremely high diastereomeric ratios and very good to excellent enantioselectivities, both of which were demonstrated to be easily improved further by crystallization. N-PMP-protected α-imino esters reacted with both cyclic and acyclic ketones to give the products in good to excellent yields. A plausible transition state to account for the observed selectivity is also presented.